The present invention generally relates to medical instruments. More particularly, the present invention relates to thoracentesis needle devices which are used in the removal of fluid from the pleural cavity and which prevent air entry into the pleural cavity during use.
The thoracentesis procedure involves incising through the chest wall, and inserting a tube or catheter through the chest wall and into the pleural cavity. By providing a negative pressure at the proximal end of the catheter, intrathoracic fluid such as blood, puss, air, and other secretions are removed from the pleural cavity. While removal of the intrathoracic fluid is desirable, at the same time it is imperative for a negative pressure to be maintained in the pleural cavity in order to permit the lungs to remain expanded such that breathing can continue. In order to maintain a negative pressure in the pleural cavity, care must be taken to avoid communication between the pleural cavity and atmospheric pressure, as a passage of air from outside the body into the pleural cavity can collapse the lung; a medical condition known as pneumothorax.
A common manner of conducting a thoracentesis procedure is to make a chest wall incision using a needle. In introducing the needle into the pleural cavity, care must be taken to avoid pushing the needle too far and puncturing the lung, as air from the lung space could escape into the pleural cavity and result in a lung collapse. In such cases it is actually possible to produce a pressure within the pleural cavity which is greater than atmospheric pressure, and cardiac compromise is a possible consequence.
A thoracentesis device which purportedly reduces possibility of lung puncture and reduces pneumothorax due to entry of air into the pleural cavity is proposed in U.S. Pat. No. 4,447,235 to Clarke. The proposed device includes a needle having a drainage opening which extends through a catheter and a through an elongated conduit connected to the catheter. The elongate conduit is provided with a seal and a manual valve. The seal, which is punctured by the needle when the needle is inserted through the elongate conduit and catheter, prevents air leakage into the pleural cavity by sealing around the needle and resealing when the needle is removed. The manual valve, when moved, permits the elongate conduit to open to a side conduit when the needle is removed, thereby permitting long term drainage of the pleural cavity. In the Clarke patent, the removal of the needle is what reduces the possibility of lung puncture.
In addition to the device proposed in the Clarke patent, devices and procedures are set forth in U.S. Pat. Nos. 4,784,156, 4,832,044, 4,840,184, and 4,844,087 to Garg. In the Garg patents, an manual in-line valve is provided, and upon retraction of the needle past the valve, the valve is turned such that entry of air into the pleural cavity is prevented.
While the prior art patents represent advances in the art, it should be appreciated that with the prior art devices, it is still relatively easy for even a skilled surgeon to puncture the lung by pushing the needle just slightly too far into the pleural cavity. In fact, even if the needle is in the pleural cavity for a short period of time, should the patient move or cough, or even take a deep breath, it is possible for the needle to puncture the lung. In addition, with the manual valve structures of the prior art, should the attending surgeon forget to properly move the valve into the desired positions as certain times, undesirable results may be obtained.
Also long known in the art are needles called "Veress" or "Veress-type" needles. Veress needles are needles with an outer needle having a sharp distal end and an inner probe which extends through the outer needle with the probe having a blunt distal end. In Veress needles, the inner probe is biased to force the blunt distal end of the probe beyond the sharp distal end of the outer needle. However, when the blunt distal end of the probe encounters dense material, the probe is forced backward and the sharp end of the needle is presented so that it can puncture the dense material. Veress needles are used in the art almost exclusively for insufflation (injection of air) of the abdomen during laparoscopy procedures, and Veress needles with manual shut-off valves are known in the art. Veress needles have also been suggested for use in a thoracentesis procedure (See, Jenkins, Jr. Douglas, et al., "Veres Nedle in the Pleural Space" Southern Medical Journal: Vol 76, No. 11, pp. 1,383-1,385 (November 1983)), although the techniques suggested therein in a test study have not gained popularity over the several years since they were reported and are not today used in common practice. Regardless of use, the Veress needle assemblies of the art have not before been modified for particular use in conjunction with withdrawal of fluid, and in particular withdrawal of fluid from the pleural cavity. Indeed, the Veress needle assemblies of the art have not been used with automatic check valves.